Abstract

Maintaining correct inflation pressure in tireshelps to keep vehicle handling, passenger comfort andbraking at its best, as well as improving fuel efficiency andtire life. Therefore it is very important that the tires arecorrectly inflated. To address this problem, in the presentstudy experimental investigations have been carried out toidentify the effect of under-inflated tires on suspensionsystem performance by measuring vertical acceleration(vibration) of the suspension system. The experimental workhas been conducted by driving a car on the road with rangeof inflation pressure at four conditions (e.g. at standardpressure (2.3bar) and at 1.5bar of passenger wheel, driverwheel and front wheels). During the experiment the signalsof tire pressure, the suspension vibration and the car speedwere measured.To analyze the signals, the Short-Time Fourier Transform(STFT) method was used to detect the effects of tire inflationon the performance of suspension. The STFT technique hasprovided time-frequency information and the frequencycomponents of the signal with relative maximum energytransmitted to the car body.The results show that, when the tires were under-inflated byapproximately 35 percent, it was significantly increased thevibration of the car body by up to 30 percent. The analysishas also shown that STFT analysis is more accurate than thespectrum analysis for distinguishing of the tire fault. Theseeffective measurements potentially will use to develop an onlinecondition monitoring system in future.